Referring to FIG. 1A, a typical IC (Integrated Circuit) package 102 includes a plurality of leads for coupling nodes of an IC die within the IC package 102 to a system external to the IC package 102. FIG. 1A shows a bottom view of the IC package 102. A first side 104 of the IC package 102 includes a first lead 106, a second lead 108, and a third lead 110. A second side 112 of the IC package 102 includes a fourth lead 114, a fifth lead 116, and a sixth lead 118. A third side 120 of the IC package 102 includes a seventh lead 122, an eighth lead 124, and a ninth lead 126. A fourth side 128 of the IC package 102 includes a tenth lead 130, an eleventh lead 132, and a twelfth lead 134. A typical IC package includes more numerous leads to a side of the IC package. However, three leads to a side of the IC package 102 are shown in FIG. 1A for clarity of illustration.
Referring to FIG. 1B, a side view of the first side 104 of the IC package 102 of FIG. 1A is shown. The side view of the first side 104 of the IC package 102 in FIG. 1B also shows a side view of the fourth lead 114 on the second side 112 of the IC package 102 and a side view of the twelfth lead 134 on the fourth side 128 of the IC package 102.
An IC package is tested for proper functionality by applying test signals to some of the plurality of leads of the IC package and by measuring resulting signals at some of the plurality of leads of the IC package. Thus, the plurality of leads of the IC package are coupled to a system for testing the IC package.
Referring to FIG. 2, the IC package 102 is mounted within an insert of a contactor floor 202 of such a system for testing an IC package. The IC package 102 is mounted on the contactor floor 202 with the plurality of leads facing up and away from the contactor floor 202. The contactor floor 202 holds the IC package 102 for moving the IC package 102 within the system for testing the IC package 102. A respective contactor pin of the system for testing the IC package is coupled to each of the plurality of leads 106, 108, 110, 114, 116, 118, 122, 124, 126, 130, 132, and 134 for coupling a corresponding lead to the system for testing the IC package. However, in FIG. 2, only a first contactor pin 204 for coupling the twelfth lead 134 of the IC package 102 and a second contactor pin 206 for coupling the fourth lead 114 of the IC package 102 to the system for testing the IC package 102 are shown for clarity of illustration.
The first contactor pin 204 is placed within a first contactor pin socket 208 that properly aligns the first contactor pin 204 to a desired position within the system for testing the IC package 102. The second contactor pin 206 is placed within a second contactor pin socket 210 that properly aligns the second contactor pin 206 to a desired position within the system for testing the IC package 102.
When the IC package 102 is in a testing position, a contacting protrusion 212 of the first contactor pin 204 makes contact with the twelfth lead 134 of the IC package 102 for coupling the twelfth lead 134 to the system for testing the IC package 102. Also, when the IC package 102 is in the testing position, a positioning protrusion 214 of the first contactor pin 204 may rest on an upper angled surface 216 of the contactor floor 202. The positioning protrusion 214 may further affect the position of the contacting protrusion 212 of the first contactor pin 204.
Similarly, when the IC package 102 is in the testing position, a contacting protrusion 218 of the second contactor pin 206 makes contact with the fourth lead 114 of the IC package 102 for coupling the fourth lead 114 to the system for testing the IC package 102. A positioning protrusion 220 of the second contactor pin 206 may rest on an upper angled surface 222 of the contactor floor 202. The positioning protrusion 220 may further affect the position of the contacting protrusion 218 of the second contactor pin 206.
The contactor floor 202 holds and moves the IC package 102 to and away from the testing position. In the testing position, a respective contactor pin makes contact with a corresponding one of each of the plurality of leads 106, 108, 110, 114, 116, 118, 122, 124, 126, 130, 132, and 134 for coupling that corresponding lead to the system for testing the IC package. In the testing position, the contactor floor moves the IC package 102 downward until the respective contactor pin makes contact with the corresponding lead of the IC package 102. Referring to FIG. 3, when the IC package 102 is not in the testing position, the contactor floor 102 moves the IC package 102 upward and away from the contactor pins. Elements having the same reference number in FIGS. 2 and 3 refer to elements having similar structure and function.
A compression spring 224 is disposed below the contactor floor 202 within an opening at the bottom of the contactor floor 202. Referring to FIG. 2, when the IC package 102 is moved to the testing position, the compression spring 224 is compressed as the contactor floor 202 is moved down with the IC package 202 toward the contactor pins. Referring to FIG. 3, when the IC package 102 is not in the testing position, the compression spring 224 is decompressed as the contactor floor 202 is moved upward with the IC package 102 away from the contactor pins.
Referring to FIG. 4, a top view of the contactor floor 202 of the prior art includes bilevel surfaces on each of the side wall of the contactor floor 202. A first indentation 402 is present on a first side wall 404 of the contactor floor 202 of the prior art, a second indentation 406 is present on a second side wall 408 of the contactor floor 202 of the prior art, a third indentation 410 is present on a third side wall 412 of the contactor floor 202 of the prior art, a fourth indention 414 is present on a fourth side wall 416 of the contactor floor 202 of the prior art.
Referring to FIGS. 3 and 4, a contactor pin fits within the indentation of a side wall of the contactor floor and slides along that side wall within that indentation as the contactor floor 202 of the prior art moves toward and away from the testing position with respect to the contactor pin. The indentation on a side wall of the contactor floor of the prior art ensures that the contactor pin is positioned sufficiently in toward the leads of the IC package 102 such that the contacting protrusion of the contactor pin makes contact with the corresponding lead of the IC package 102 when the IC package 102 is in the testing position with respect to the contactor pins.
However, as the contactor floor 202 of the prior art moves up and down for moving the IC package 102 toward and away from the testing position, the contacting protrusion of the contactor pin slides and scrapes along the corresponding lead. Referring to FIG. 5, the contactor floor 202 is moving the IC package 102 up with respect to the contactor pins toward the testing position. During such movement, the contacting protrusion 212 of the first contactor pin 204 scrapes along the twelfth lead 134 of the IC package 102, and the contacting protrusion 218 of the second contactor pin 206 scrapes along the fourth lead 114 of the IC package 102.
Referring to FIG. 6, the contactor floor 202 is moving the IC package 102 down with respect to the contactor pins away from the testing position after the IC package 102 has been tested. During such movement also, the contacting protrusion 212 of the first contactor pin 204 scrapes along the twelfth lead 134 of the IC package 102, and the contacting protrusion 218 of the second contactor pin 206 scrapes along the fourth lead 114 of the IC package 102.
Unfortunately, such scraping of the contactor pins along the leads results in solder flaking at the leads. With such repeated scraping of the contactor pins against the leads of an IC package during testing of numerous IC packages, the flaking solder particles build up to result in visible solder flakes at the leads of the IC package. Such visible solder flakes are considered to be an undesired cosmetic defect for an IC package.
In the prior art, such undesired solder flakes are visibly detected and manually removed from the IC package with a tweezer. In addition, to prevent formation of such solder flakes, the contactor pins are routinely cleaned or replaced before visibly noticeable solder flakes form on the leads of the IC package. However, such manual detection and removal of the solder flakes and the cleaning or replacement of the contactor pins slows down production of IC packages. However, testing of the IC package is also desired before the IC package is shipped to a customer.
Thus, a mechanism is desired for minimizing the formation of undesired solder flakes at the leads of an IC package during movement and placement of the IC package to the contactor pins within a system for testing the IC package.